This invention is generally directed to toner compositions, and more specifically, the present invention relates to developer compositions having incorporated therein toner compositions comprised of poly(alpha-olefin) copolymer resins. More specifically, in one embodiment of the present invention there are provided developer compositions formulated by admixing toner compositions containing toner polymeric resins, and carrier components. In one specific embodiment of the present invention there are provided toner compositions with poly(alpha-olefin) derived copolymers of the formula poly(A.sub.n --B.sub.m), that is for example copolymers such as (A.sub.n --B.sub.m) wherein n represents the approximate number of A monomers of type A, and m represents the approximate number of B monomers of type B, which copolymer compositions in embodiments enable a desirable low fusion and fusing energy; are easily jettable or processable into toner compositions; are optically opaque providing, for example, reduced objectionable gloss to color and particularly to matte black copies and prints; and with the copolymers illustrated herein there can, in several embodiments, be fabricated brittle, rubbery, or other similar toner polymers with an optimized melt viscosity profile, that is for example added monomers that extend the copolymer chain and increase the molecular weight and melt viscosity of the resulting polymer without substantially adversely influencing the fusion and fusing properties of the toner. Also, toner compositions formulated with the aforementioned copolymers have similar advantages as illustrated herein. Thus, for example, the toner compositions of the present invention possess low fusing temperatures, and therefore lower fusing energies are required for fixing, thus enabling less power consumption during fusing, and permitting extended lifetimes for the fuser systems selected and therefore enhanced copy machine reliability. Accordingly, therefore, the toners of the present invention in embodiments can be fused (fuser roll set temperature) at temperatures of between 200.degree. and 250.degree. F. or less, as compared to many currently commercially available toners which fuse at temperatures of from about 300.degree. to about 325.degree. F. The aforementioned polymers enable fusing systems that do not require a silicone or related oil fluid to release fused copies and toner from the fuser roll. Specifically, the copolymers poly(A.sub.n --B.sub.m), that is of the formula (A.sub.n --B.sub.m), of the present invention wherein A is a first monomer, such as eicosene, and B is a second monomer such as styrene, eicosene, eicosene derivatives selected from the group hydroxy, halide, quaternary ammonium, amine and amide, or undecylenic acid or undecylenic acid derivatives selected from the group hydroxy, halide, quaternary ammonium, amine, amide, carboxylic acid, alkali metal salts, alkyl and aryl acid esters, and trialkylsilyl acid ester, which poly(alpha-olefin) copolymers have determined, for example, upon the amount of catalyst used an estimated number average molecular weight of from about 2,000 to about 1,500,000 and preferably from about 10,000 to about 100,000. Also, the toner and developer compositions of the present invention are particularly useful in electrophotographic imaging and printing systems, especially xerographic imaging processes that are designed for the generation of low energy fusing, preferably matte finish black images.
The electrostatographic process, and particularly the xerographic process, is well known. This process involves the formation of an electrostatic latent image on a photoreceptor, followed by development, and subsequent transfer of the image to a suitable substrate. Numerous different types of xerographic imaging processes are known wherein, for example, insulative developer particles or conductive toner compositions are selected depending on the development systems used. Moreover, of importance with respect to the aforementioned developer compositions are the appropriate triboelectric charging values associated therewith, as it is these values that enable continued constant developed images of high quality and excellent resolution, and admixing characteristics. Specifically, thus toner and developer compositions are known, wherein there are selected as the toner resin styrene acrylates, styrene methacrylates, and certain styrene butadienes including those available as Pliolites.RTM.. Other resins have also been selected for incorporation into toner compositions inclusive of the polyesters as illustrated in U.S. Pat. No. 3,590,000. Moreover, it is known that single component magnetic toners can be formulated with styrene butadiene resins, particularly those resins available as Pliolite. In addition, positively charged toner compositions containing various resins, inclusive of certain styrene butadienes and charge enhancing additives, are known. For example, there are described in U.S. Pat. No. 4,560,635, the disclosure of which is totally incorporated herein by reference, positively charged toner compositions with distearyl dimethyl ammonium methylsulfate charge enhancing additives. The '635 patent also illustrates the utilization of suspension polymerized styrene butadienes for incorporation into toner compositions, reference for example working Example IX contained therein.
Numerous U.S. Pat. Nos. are in existence that illustrate toner compositions with various types of toner resins including, for example, 4,104,066, polycaprolactones; 3,547,822, polyesters; 4,049,447, polyesters; 4,007,293, polyvinyl pyridine-polyurethane; 3,967,962, polyhexamethylene sebaccate; 4,314,931, polymethyl methacrylates; Reissue 25,136, polystyrenes; and 4,469,770, styrene butadienes.
In a patentability search report the following United States patents were listed:
______________________________________ U.S. Pat. No. 3,967,962 Patentee: O'Malley Issued: July 6, 1976 U.S. Pat. No. 4,810,612 Patentee: Ueda et al. Issued: March 7, 1989 U.S. Pat. No. 4,448,871 Patentee: Tamaki et al. Issued: May 15, 1984 U.S. Pat. No. 3,853,778 Patentee: Buckley et al. Issued: December 10, 1974 U.S. Pat. No. 4,610,944 Patentee: Matsumoto et al. Issued: September 9, 1986 ______________________________________
O'Malley, for example, discloses an imaging process employing a semicrystalline toner resin comprised of segmented block or graft copolymers consisting of at least one crystalline or crystallizable polymeric segment chemically linked, typically by a urethane coupling agent, to at least one amorphous polymeric segment. Specifically disclosed is, for example, a toner resin comprised of a copolymer containing poly(1-hexadecene).
Ueda discloses toner compositions made from resins comprised of graft modified polyolefin waxes, wherein polyolefins having 2 to 10 carbon atoms are preferred, and more specifically polyolefins prepared from alpha-olefins having 2 to 10 carbon atoms and grafted thereto are monomers selected from the group consisting of acrylonitrile or methacrylonitrile, aromatic carboxylic acid vinyl ester and unsaturated carboxylic acid esters.
Tamaki discloses a toner composition and method for making said toner wherein the toner resin is comprised of random copolymers comprised of alpha olefins in the alkene series of C.sub.2 to C.sub.10 and isomers thereof.
Buckley, for example, discloses a toner resin comprised of a polymer selected from the group consisting of a crystalline homopolymer or copolymer having an amorphous backbone and side-chain crystallinity derived from polymerizable monomers having at least 14 carbon atoms.
Matsumoto discloses a process for producing a toner composition that comprises initially forming a hot melt mixture of monomeric long chain hydrocarbons or alpha olefins such as eicosene, a colorant and a dispersant.
Of interest is U.S. Pat. No. 4,529,680, which discloses magnetic toners for pressure fixation containing methyl-1-pentene as the main component. More specifically, there is illustrated in this patent, reference column 2, beginning at line 66, magnetic toners with polymers containing essentially methyl-1-pentene as the main component, which polymer may be a homopolymer or copolymer with other alpha-olefin components. It is also indicated in column 3, beginning at around line 14, that the intrinsic viscosity of the polymer is of a specific range, and further that the melting point of the polymer is in a range of 150.degree. to 240.degree. C., and preferably 180.degree. to 230.degree. C. Other U.S. Pat. Nos. of background interest include 3,720,617; 3,752,666; 3,788,994; 3,983,045; 4,051,077; 4,108,653; 4,258,116 and 4,558,108.
Furthermore, a number of different carrier particles have been illustrated in the prior art, reference for example the 3,590,000 patent mentioned herein; and U.S. Pat. No. 4,233,387, the disclosure of which is totally incorporated herein by reference, wherein coated carrier components for developer mixtures, which are comprised of finely divided toner particles clinging to the surface of the carrier particles, are recited. Specifically, there are disclosed in this patent coated carrier particles obtained by mixing carrier core particles of an average diameter of from between about 30 microns to about 1,000 microns with from about 0.05 percent to about 3.0 percent by weight based on the weight of the coated carrier particles of thermoplastic resin particles. More specifically, there are illustrated in the '387 patent processes for the preparation of carrier particles by a powder coating process; and wherein the carrier particles consist of a core with a coating thereover comprised of polymers. The carrier particles selected can be prepared by mixing low density porous magnetic, or magnetically attractable metal core carrier particles with from, for example, between about 0.05 percent and about 3 percent by weight based on the weight of the coated carrier particles of a polymer until adherence thereof to the carrier core by mechanical impaction or electrostatic attraction; heating the mixture of carrier core particles and polymer to a temperature, for example, of between from about 200.degree. F. to about 550.degree. F. for a period of from about 10 minutes to about 60 minutes enabling the polymer to melt and fuse to the carrier core particles; cooling the coated carrier particles; and thereafter classifying the obtained carrier particles to a desired particle size. In U.S. Pat. Nos. 4,937,166 and 4,935,326, the disclosures of which are totally incorporated herein by reference, there are disclosed carrier particles comprised of a core with a coating thereover comprised of a mixture of a first dry polymer component and a second dry polymer component not in close proximity to the first polymer in the triboelectric series. Therefore, the aforementioned carrier compositions can be comprised of known core materials including iron with a dry polymer coating mixture thereover. Developer compositions can be generated by admixing the aforementioned carrier particles with a toner composition comprised of the resin particles of the present invention and pigment particles. Other U.S. Pat. Nos. of interest include 3,939,086, which discloses steel carrier beads with polyethylene coatings, see column 6; 3,533,835; 3,798,167; 3,918,968; 3,922,382; 4,238,558; 4,310,611; 4,397,935 and 4,434,220, the disclosures of which are totally incorporated herein by reference.
In copending application U.S. Ser. No. 751,922 (abandoned) entitled "Developer Compositions With Specific Carrier Particle Developers", the disclosure of which is totally incorporated herein by reference, there are illustrated toners with styrene butadiene copolymers, pigment particles inclusive of magnetites, charge control additives, and carrier particles containing a core with a coating thereover of vinyl copolymers or homopolymers, such as vinyl chloride/vinyl acetate.
Additionally of interest with respect to the toner resins and toners of the present application are the semicrystalline polyolefin resins or blends thereof illustrated in U.S. Pat. No. 4,952,477 and copending applications U.S. Pat. No. 4,990,424 (D/87152), and liquid glass multiblock copolymer resins illustrated in U.S. Ser. No. 587,194 (D/89064), the disclosures of which are totally incorporated herein by reference. More specifically, in the '477 patent there are disclosed toners with semicrystalline polyolefin polymer or polymers with a melting point of from about 50.degree. to about 100.degree. C., and preferably from about 60.degree. to about 80.degree. C. with the following formulas wherein the subscript x is a number of from about 250 to about 21,000; the number average molecular weight is from about 17,000 to about 1,500,000 as determined by GPC; and the M.sub.w /M.sub.n dispersability ratio is from about 2 to about 15.
______________________________________ I. Polypentenes - (C.sub.5 H.sub.10).sub.x II. Polytetradecenes - (C.sub.14 H.sub.28).sub.x III. Polypentadecenes - (C.sub.15 H.sub.30).sub.x IV. Polyhexadecenes - (C.sub.16 H.sub.32).sub.x V. Polyheptadecenes - (C.sub.17 H.sub.34).sub.x VI. Polyoctadecenes - (C.sub.18 H.sub.36).sub.x VII. Polynonadecenes - (C.sub.19 H.sub.38).sub.x ; and VIII. Polyeicosenes - (C.sub.20 H.sub.40).sub.x. ______________________________________
Examples of specific semicrystalline polyolefin polymers illustrated in this copending application include poly-1-pentene; poly-1-tetradecene; poly-1-pentadecene; poly-1-hexadecene; poly-1-heptadecene; poly-1-octadene; poly-1-nonadecene; poly-1-eicosene; mixtures thereof; and the like.
Principal advantages of the copolymers of the instant invention over the aforementioned crystalline and semicrystalline copolymers include improved jetting rate; improved control of tribocharging properties of the resultant toner composition by incorporation of functional groups into the resin; improved control of the melt viscosity and rheology providing a broader fusing latitude of the toner composition; and a reduced tendency of the resultant toner composition to vinyl offset, that is to transfer from paper to a vinyl surface as found in ring notebook binders, when fused to, for example, paper copy sheets.
Although the above described toner compositions and resins are suitable for their intended purposes, including those of U.S. Pat. No. 4,592,477 and copending application U.S. Ser. No. 231,428, U.S. Pat. No. 4,990,424 there continues to be a need for toner and developer compositions containing new resins. More specifically, there is a need for toners which can be fused at lower energies than many of the presently available resins selected for toners. There is also a need for resins that can be selected for toner compositions which are low cost, nontoxic, nonblocking at temperatures of less than 50.degree. C., jettable, melt fusible with a broad fusing latitude, cohesive above the melting temperature, and triboelectrically chargeable and stable. In addition, there remains a need for toner compositions which can be fused at low temperatures, that is for example of between 200.degree. and 250.degree. F. or less, as compared to a number of toners presently in commercial use, which require fusing temperatures of about 300.degree. to 325.degree. F., thereby enabling, with the compositions of the present invention, the utilization of lower fusing temperatures, and lower fusing energies permitting less power consumption during fusing, and allowing the fuser system, particularly the fuser roll selected, to possess extended lifetimes. Another important need exists for toner resins which enable fuser systems to function without silicone or related release agent oils that function to release fused copies from the fuser roll. Another need resides in the provision of developer compositions comprised of the toner compositions illustrated herein, and carrier particles. There also remains a need for toner and developer compositions containing additives therein, for example charge enhancing components, thereby providing positively, or negatively charged toner compositions. Furthermore, there is a need for toner and developer compositions with copolymers that will enable the generation of solid image area with substantially no background deposits, and full gray scale production of half tone images in electrophotographic imaging and printing systems. Also, the toner compositions of the present invention may be selected for imaging and printing processes wherein silicone oils, or release fluids are avoided, or minimized.
There is also a need for polymers, in particular copolymers, and mixtures of the aforementioned copolymers with melting points of from about 30.degree. to about 100.degree. C., and preferably from about 40.degree. to about 60.degree. C.; and wherein toner compositions containing the aforementioned resins can be formulated into developer compositions which are useful in electrophotographic imaging and printing systems, and wherein fusing can, for example, be accomplished by flash, radiant, with heated ovens, and cold pressure fixing methods.